As the feature size of metal oxide semiconductor field effect transistor (MOSFET) devices continues to decrease, the short channel effect becomes a critical issue in the performance of MOSFET devices. A Fin Field Effect Transistor (FinFET) device has good gate control capability and can effectively inhibit the short channel effect. Thus, FinFET devices are generally used in the design of smaller-sized semiconductor components.
However, semiconductor devices tend to be more susceptible to the punch through effect with reduced feature sizes. In order to suppress the punch through effect, a channel stop ion implantation can be performed at the bottom of the fin. However, the present inventor discovered that dopants will easily diffuse into the channel region disposed above when an annealing process is performed after the channel stop ion implantation, thereby affecting the performance of the device.